Method and apparatus for false twisting textile yarns and product obtained thereby

ABSTRACT

This invention concerns a process and device for the production of a new textured thread with open structure wherein thread of thermoplastic material in a substantially plastic state is subjected to at least two directly consecutive false twisting operations either in the same or opposite directions. The invention also concerns the product obtained thereby.

United States Patent 1151 3,685,273 Neveux [451 Aug. 22, 1972 [54] METHOD AND APPARATUS FOR 3,009,312 11/1961 Seem et a1. ..57/34 X FALSE TWISTING TEXTILE YARNS 3,029,591 4/1962 Scragg et al. ..57/77.4 X AND PRODUCT OBTAINED THEREBY 3,066,473 12/ 1962 Maeda ..57/77.4 3,114,231 12/1963 Selling et a1. ..57/77.4 X 2 I t [7 1 "7" f Neveux Rlorges.Ffi mce 3,535,866 10/1970 Tsuruta et a1 ..57/77.4 x Asslgnee: Moulmage 9t Retroderle 99, 3,527,043 9/1970 Sabaton ..57/77.4

Chavanoz (lsere), France [22] Filed: March 1970 FOREIGN PATENTS OR APPLICATIONS [211 App]. NO-Z 23,418 1,455,202 9/1966 France ..57/77.3

Primary Examiner-Werner H. Schroeder [30] Foreign Application Priority Data Attorney-Norman C. Armitage and H. William Petry March 28, 1969 Fran e ..69()9520 I c 57 ABSTRACT [52] US. Cl. ..57/77.4, 57/ 157 TS This invention concerns a process and device for the [5 CL t 3 "D0111 pr d cti n of a new Open Struc- [58] held of Search "57/34 34 R1 ture wherein thread of thermoplastic material in a sub- 157 157 Ts stantially plastic state is subjected to at least two directly consecutive false twisting operations either in [56] References Clted the same or opposite directions. The invention also UNITED STATES PATENTS concerns the product obtained thereby.

2,936,570 5/1960 Arthur et a1 ..57/157 8 Claims, 5 Drawing Figures PAIENTEBmszz um SHEEI 1 0F 5 FIGJ INVENTOR JACQUES NEVEUX PATENTEDRUGZZ r 1 v 3.685.273

' SHEET 20F 5 FIGQZ /A I 22 1e INVENTOR JACQUES NE JEUK PATENTEDmszz m2 SHEET 3 OF 5 INVENTOR JACQUES NEVEUX PATENTEnAuszzmz A 3.685273 SHEET S [If 5 INVENTOR JACQUES NEVEUX METHOD AND APPARATUS FOR FALSE TWISTING TEXTILE YARNS AND PRODUCT OBTAINED THEREBY The present invention aims at a new process for the production of textured threads, a device for the execution of this process, as well as the new product thus obtained.

The new thread according to the invention is particularly useful for the manufacture of millinery articles, but, of course, its application is not limited to a single kind of use.

It is well known that articles of millinery are generally required to have great flexibility and a fair elasticity, but principally much spring, that is a great power of elastic return.

Now, one knows how to make very elastic threads for example by twisting, fixing and untwisting of threads of thermoplastic material.

Unfortunately these threads remain quite compact, leading to an appearance and a feel less pleasant than desired.

It has therefore been attempted to modify the appearance and characteristics of threads obtained either by a second fixing treatment which has the effect of I reducing their elasticity, or by a second treatment of false twisting, applied in continuous after the first, the second false twisting operation being done with a twisting in the opposite direction and to a lesser extent than thefirst, and with fixing at a lower temperature than the fixing temperature of the first false twisting operation.

Eventually this double false twisting can also be combined with a third texturing operation, for example by inversion of twisting.

Also the processes of false twisting in continuous lead to a thread with residual torsion couple, generally called twisting," or thread with torque effect, which expressions shall be used below.

These threads can be used by alternating, during knitting, the rows of threads of twisting couple of opposite directions, which in certain cases has the advantage of imparting to the articles thus obtained a very great elasticity, while the threads themselves are relatively not very elastic.

But most of the time the torque effect is considered as a disadvantage to be avoided.

Now one has found-and this is the object of the present invention-a new texturing process which consists in thermically treating a thread of thermoplastic material to bring it to a substantially plastic state, and subjecting it to at least two directly consecutive operations of false twisting.

These two false twisting operations can be in the same direction or in opposite directions.

By false twisting in the same direction is meant that the two operations of twisting and of untwisting of each of the false twistings are respectively in the same direction. In this case obviously, the two false twistings have cumulative effects, whereas in the case where the false twistings are in opposite directions, they have effects with the tendency to undo each other, particularly in the case of an even number of false twistings of opposite directions, the torque effects created by each false twisting operation cancelling each other.

On the other hand, more or less pronounced torque effects can be obtained by subjecting the thread to false twistings in the same direction, or to an odd number of false twistings in opposite directions.

These operations of false twisting can particularly be done on a same texturing organ, such as a texturing organ by false twisting by friction.

According to a form of the process of the invention, a thermoplastic textile thread is textured by means of an annular friction surface in rotation about a fixed axis, this process being characterized in that the thread is put consecutively in contact with at least two points of the friction surface.

It results therefrom that the thread is subjected to at least two operations of false twisting in opposite directions or in same direction.

The points of contact of the thread with the friction surface can be situated at any point of said surface, but

advantageously according to a simple geometric distribution, for example in the case of two points of contact, they are diametrically opposed.

The length of thread included between the points of twisting by friction depends on the operating condi tions, such as the speed of supply of the thread, nature of the thread, temperature of the thermic treatment ahead of the twisting spindle. This length depends also on the effect desired, produced by a slight cooling of the thread occuring during its passage through two points offalse twisting.

According to a particular form of execution of the present process, this distance can be variable, so as to modify the effect produced on the thread, or the thread can be cooled, for example by an intermittent jet of cold air between the two operations of false twisting.

One may also further subject the thread to a second thermic treatment, continuous or discontinuous, in the relaxed or stretched state, on the thread itself or on the knitted article.

One may use threads of any artificial or synthetic thermoplastic material, but the present process is of particular interest for multifilament threads.

According to a particularly advantageous form of the process of the invention, the thread traverses 2n times the annular space limited by the friction surface in rotation, n being a whole number which can be equal to zero.

A new multifilament textured thread is obtained which is also part of the invention, having a threedimensional texture and a strong power of elastic return, characterized in that this multifilament has an open structure, i.e., the component filaments are separate, the cohesion of the multifilament being due solely to the hooking of the different filaments and not to a common twisting.

As has been mentioned above, this thread can be without torque effect, i.e., it has a stable configuration in the free state, without tendency to snarl, or on the contrary it can have a torque" effect and therefore a tendency to twist when in the free state.

In practice the process of the invention can apply to any multifilament thread generally used in classical texturing, such as thread with a small number of filaments, as is the case for threads intended for the manufacture of hosiery, or threads with a fairly large number of filaments such as those intended for normal applications of millinery or weaving.

The process according to the invention can be executed by means of a device of falsetwisting by friction.

Advantageously, this device of false twisting by friction comprises at least one annular surface of friction in rotation over itself about a fixed axis, whose faces for the entrance and outlet of the thread in the annular space defined by this surface are blended together, this annular surface being in contact at at least two points with a thread moving under tension, and is characterized in that this friction surface is associated with means to guide the thread in the annular space.

This false twisting spindle can be formed by a revolving tube driven in rotation, this tube having a hollowed terminal part covered on the inside by a ring made of a material with a high coefficient of friction, and the guiding means can be formed by a device including guiding arms staggered with respect to one another by a certain angle, these guiding arms sliding in a fixed tube and each having an eyelet for the passage of the thread.

Also in the case of the process according to which the thread traverses 2 n times the annular space limited by the surface of friction in rotation, one uses a'device characterized by the fact that the elements of passage of the thread, carried by the thread guiding means in the annular space, are situated, with respect to the face of entrance and outlet of the thread, on the same side as the friction ring.

By entrance face of the thread in the annular space is meant the face which the thread traverses when it penetrates for the first time in this annular space. By opposition, the outlet face is the face which the thread traverses when it comes out for the last time from this annular space. Practically, the annular surface of friction is circular.

In simple manner, the false twisting spindle is formed by a revolving tube, driven in rotation for example by a belt. This tube has a hollowed terminal part, covered on the inside by a ring made of a material with high coefficient of friction but not abrasive, such as reinforced elastomer or a ceramic based on aluminum or titanium oxide.

In the preferred form of execution, the means for guiding the thread in the annular space are formed by several guiding arms staggered with respect to one another by a certain angle, and having at one end an eyelet for the passage of the thread. The guiding arms can slide inside a fixed hollow tube so that, in the rest position, they are situated outside the hollow space of the spindle so as to facilitate the threading of the thread.

In running position, these arms are engaged inside this hollow space of the spindle so as to keep the thread inside the annular space in contact with the friction element.

The guiding arms are held in position with respect to one another by means of an elastic element, or a stop, or a ramp, or any equivalent means.

According to another form of execution, these guiding anns can be mounted on a simple or multiple element sliding inside the central shaft of the spindle, particularly inside the annular space.

These arms can be mounted dissymmetrically and can be of different lengths, so as to provide for example different arcs of contact during the two operations of false twisting.

One may also provide arms serving solely to extend I the travel between two operations of false twisting,

these arms having an adjustable position.

Of course, one would not issue from the framework of the present invention if one used a classical spindle for texturing by friction whose annular space is traversed by the thread, or used more or less closely spaced distinct friction surfaces, according to the effect desired.

The spooling device is of any known type, but must allow high receiving speeds going up to L000 m/min. corresponding to speeds of production of the thread according to the invention.

But the present invention will be better understood with the aid of the attached examples of execution and diagrams:

FIG. 1 represents a general false twisting device.

FIGS. 2 and 3 give a detailed view of a spindle of false twisting by friction and of means to guide the thread through said spindle in the case of two false twistings in opposite directions.

FIG. 4 is a detailed view of a spindle identical to that illustrated in FIGS. 2 and 3, but associated with guiding means guiding the thread through said spindle in the case of two false twistings in the same direction.

FIG. 5 illustrates an example of execution according to which the thread traverses a friction ring driven peripherally.

As can be seen in FIG. 1 a thread 1 drawn from a spool 2 passes over guides 3 and 4, then through a belt feeder 5 before being directed by a guide 6 into a heating chamber 7 where it is heated thermically.

At the outlet of the chamber 7 the thread is textured in the device 8 according to the invention before traversing a guiding eyelet 9 and a second belt feeder 10, then being directed by guides 11 and 12 over a spooling device comprising a thread guide 13 moving to-and-fro, a winding spool 14 as well as a pressure roll 15.

The texturing device 8 according to the invention (See FIGS. 2 and 3) is formed by a friction ring 16 mounted in a spindle l7, driven in rotation by means of a device which is not represented.

The guiding means are formed by two arms 18 and 19 with eyelets 20 and 21 for the passage of the thread. These two arms can slide inside the hollow tube 22.

Thus the thread 1 at the outlet of the heating chamber 7 passes successively over a guide 23 then over the friction ring 16 in the eyelets 20 and 21 respectively in arms 18 and 19, again over the friction ring 16 and finally over a guide 24. Suitable jet means, shown schematically at 36, may be suitably positioned adjacent the yarn path to provide an intermittent jet of cold air to the thread to cool the same between the two operations of false twisting, as aforementioned.

According to another form of execution (See FIG. 4) the thread is guided so as to have an S trajectory inside the spindle 17. The thread 1 at its outlet from the heating chamber, downstream of the guide 23 passes successively over the friction ring 16 then in an eyelet 25 in the angled arm 26, and in an eyelet 27 in arm 28, the eyelet 27 being situated ahead of the spindle with respect to the friction ring.

In this manner, the thread is subjected on ring 16 to a second false twisting in the same direction, before being guided out of the annular space by an eyelet 29 and a return guide 30 carried by a third sliding arm 31. Such an arrangement allows to keep the same spindle, therefore the same general device, with the same production speeds as in the previous case. Obviously, in this case, one may use a spindle with peripheral drive, such as illustrated in FIG. 5, where at the outlet of eyelet 27 the thread is subjected to a second false twisting, then is recalled directly by coming out through the opposite face of the annular surface. In this case the spindle is formed by a friction ring 32 arranged in a tube 33, mounted rotating on a roller 34 and driven by its periphery, for example by a belt passing in a throat 35 By means of this device the following examples have been executed:

EXAMPLE 1 Using a spindle according to FIGS. 2 and 3, comprising a friction ring of inside diameter equal to 28 mm, made of reinforced elastomer material, one treats a thread of polyhexamethylene adipamide (nylon 66) 22 dtex/3 filaments of initial twisting 12 turns per meter (twisting Z) according to the following operating conditions:

Speed of rotation of the spindle 10,830 r.p.m. Temp. of oven inside heating chamber 200 degrees C (Speed of the second thread delivery means Speed of the first thread delivery means 5) X 100 105% Spooling speed 315 meters/min The thread obtained has a break resistance of 5.2 g/dtex and an elasticity of 1 13 percent measured in the following manner:

A skein of thread is made which is immersed in the relaxed state for 10 minutes in water kept at 65 C.

This skein is then rinsed, drained for 1 minute and dried in an oven for l0 minutes at 65 C.

The skein is then suspended for 5 minutes in a laboratory where the temperature is to 22 C and the humidity is 65 to 70 percent. The skein is subjected for 2 minutes to a load of 0.225 g/dtex, a length L is thus measured, then the previous load is replaced with a second load of 0.0018 g/dtex, and a second length L is measured.

The elasticity is given by the ratio Furthermore, the thread obtained has no torque effect, this effect being measured in the following manner:

A skein is made of three turns on a float of 3 meter perimeter, then a weight of 4.8 kg is suspended to this skein. Then the skein is suspended, it is allowed to become stabilized, and it is unwound counting the number of turns.

EXAMPLE 2 This example is identical to the first one as to the operating conditions, except for the temperature of the oven which is 180 C, but here one uses a thread of polycaprolactam (nylon 6) 22 dtex/3 filaments. The resistance of the thread obtained is of 4.5 g/dtex and its elasticity is 1 l0 percent, and its torque effect is equal to zero.

EXAMPLE 3 This example is identical to Example 2 except that the friction ring is of ceramic. The resistance of the thread is 3.6 g/dtex and its elasticity is 108 percent, and

. its torque" effect is nil.

It can be seen therefore that the resistance of the thread has dropped a little, on the other hand the duration of life of the ring has increased considerably, and in particular its surface state after use remains unchanged, which ensures a better uniformity in the quality of the thread.

EXAMPLE 4 The same texturing device equipped with a spindle according to Example 1 is used, but a polyethylene terephthalate thread 22 dtex/4 filaments is treated according to the following operating method:

Speed of rotation of the spindle 8,220 r.p.m. Oven temp. inside the heating chamber 200 degrees C (Speed of the second thread 'delivery means 10 Speed of the first thread delivery means 5) X 104% Spooling speed 250 meters/min The thread obtained has a break resistance of 4.5 g/dtex, and elasticity of 139 percent and no torque effect.

EXAMPLE 5 The operating conditions remain identical to those of the previous example except that the thread is guided according to the device of FIG. 4, the thread being subjected to two false twistings in the same direction.

The thread obtained has a break resistance of 4.5 g/dtex, and elasticity of 176 percent and a torque effect of turns measured under the conditions defined above.

EXAMPLE 6 With the same device as that used in Example 4, and subjecting the thread to two false twistings in opposite directions, a polyethylene terephthalate thread 167 dtex/30 filaments is treated according to the following general operating conditions:

Spool speed 4,l00 r.p.m. Oven temp. inside the heating chamber 200 degrees C (Speed of the second thread delivery means 10 Speed of the first thread delivery means 5) X 100 l04% Spooling speed 234 meters/min uuncn ruA-n THAT WHICH IS CLAIMED IS:

1. A process for texturing thermoplastic threads comprising the steps of rotating an annular frictional surface about its central axis, heating a length of thermoplastic thread, passing a running length of the heated thread into contact with the rotating annular surface to twist the thread about its longitudinal axis, passing the thread 'out of contact with the annular surface, intermittently cooling the thread while out of contact with the annular frictional surface, and again passing the thread into contact with the rotating annular surface to twist the thread about its longitudinal axis, thereby subjecting the thread to at least two consecutive operationsof false twist.

2. Apparatus for frictionally false twisting a running length of thread comprising means defining an annular frictional surface, means for rotating the annular surface about its central axis, and means for guiding the thread into engagement with the annular frictional surface at at least two spaced points to impart consecutive twist to the thread about its longitudinal axis, said guiding means comprising plural guide arms supported on one side of said annular frictional surface in angular staggered relation with respect to each other and means for moving said guide arms toward and away from said annular frictional surface to direct thread into and out of engagement therewith.

3. Apparatus as defined in claim 2 wherein said means for moving said guide arms comprises a hollow tube, and end portions of said guide arms being slidable along said hollow tube to telescopically extend and retract the guide arms for movement into and out of the space bounded by said annular frictional surface.

4. Apparatus as defined in claim 2 wherein said guide means include at least three guide arms, eyelets on each of said guide arms for engaging and guiding thread, and said moving means including means for positioning some of the eyelets of said guide arms on one side of the space bounded by said annular frictional surface and some of the eyelets on the other side of said space to define paths of multiple passage of the thread through the bounded space.

' 5. A process for texturing threads comprising the steps of rotating an annular frictional surface about its central axis, heating a length of thermoplastic thread, passing a running length of the heated thread into the space bounded by the annular surface and reversing the direction of travel of the thread through the space to contact the thread with the rotating surface at least twice to twist the thread about its longitudinal axis.

-6. A process as defined in claim 5 wherein the direction of the travel of the thread is reversed by passing the thread in oppositedirections relative to the central axis of the rotating surface at least 2n times, n being a whole number.

7. Apparatus for false twisting a running length of thread comprising means defining an annular frictional surface, means for rotating the surface about its central axis, and means for guiding the thread through the space bounded by the annular surface in reversing directions to contact the thread with the frictional surface at at least two spaced points to impart twist thereto.

8. Apparatus as defined in claim 7 wherein said means defining said annular surface comprises a cupshaped member, the internal side portions of said member being comprised of a member having a high coefficient of friction. 

1. A process for texturing thermoplastic threads comprising the steps of rotating an annular frictional surface about its central axis, heating a length of thermoplastic thread, passing a running length of the heated thread into contact with the rotating annular surface to twist the thread about its longitudinal axis, passing the thread out of contact with the annular surface, intermittently cooling the thread while out of contact with the annular frictional surface, and again passing the thread into contact with the rotating annular surface to twist the thread about its longitudinal axis, thereby subjecting the thread to at least two consecutive operations of false twist.
 2. Apparatus for frictionally false twisting a running length of thread comprising means defining an annular frictional surface, means for rotating the annular surface about its central axis, and means for guiding the thread into engagement with the annular frictional surface at at least two spaced points to impart consecutive twist to the thread about its longitudinal axis, said guiding means comprising plural guide arms supported on one side of said annular frictional surface in angular staggered relation with respect to each other and means for moving said guide arms toward and away from said annular frictional surface to direct thread into and out of engagement therewith.
 3. Apparatus as defined in claim 2 wherein said means for moving said guide arms comprises a hollow tube, and end portions of said guide arms being slidable along said hollow tube to telescopically extend and retract the guide arms for movement into and out of the space bounded by said annular frictional surface.
 4. Apparatus as defined in claim 2 wherein said guide means include at least three guide arms, eyelets on each of said guide arms for engaging and guiding thread, and said moving means including means for positioning some of the eyelets of said guide arms on one side of the space bounded by said annular frictional surface and some of the eyelets on the other side of said space to define paths of multiple passage of the thread through the bounded space.
 5. A process for texturing threads comprising the steps of rotating an annular frictional surface about its central axis, heating a length of thermoplastic thread, passing a running length of the heated thread into the space bounded by the annular surface and reversing the direction of travel of the thread through the space to contact the thread with the rotating surface at least twice to twist the thread about its longitudinal axis.
 6. A process as defined in claim 5 wherein the direction of the travel of the thread is reversed by passing the thread in opposite directions relative to the central axis of the rotating surface at least 2n times, n being a whole number.
 7. Apparatus for false twisting a running length of thread comprising means defining an annular frictional surface, means for rotating the surface about its central axis, and means for guiding the thread through the space bounded by the annular surface in reversing directions to contact the thread with the frictional surface at at least two spaced points to impart twist thereto.
 8. Apparatus as defined in claim 7 wherein said means defining said annular surface comprises a cup-shaped member, the internal side portions of said member being comprised of a member having a high coefficient of friction. 